1. Field of the Invention
The present invention relates to an illumination apparatus, a display apparatus and a projection display apparatus, each including a solid-state light source and a light valve which modulates a light emitted from the solid-state light source.
2. Description of the Related Art
There has heretofore been known a display apparatus including: a solid-state light source such as an LED (Light Emitting Diode) and an LD (Laser Diode); and a light valve which modulates a light emitted from the solid-state light source. Here, the solid-state light source generates heat when power is supplied thereto. As an operating temperature of the solid-state light source is increased, an amount of a light emitted from the solid-state light source is reduced.
Therefore, there has been proposed a display apparatus including a cooling device, such as a Peltier element, which cools a solid-state light source in order to suppress reduction in a light amount due to an increase in an operating temperature of the solid-state light source (see, for example, claims 6 and 7, Paragraph [0024] and the like in Japanese Patent Application Publication No. 2005-149943).
To be more specific, in the display apparatus described above, cooling power of the cooling device is controlled so as to allow the amount of a light emitted from the solid-state light source to approach a target light amount. Therefore, the amount of the light emitted from the solid-state light source is maintained constant.
Recently, from the viewpoint of environmental consideration and the like, reduction in power consumption of the display apparatus has been demanded.
However, in the display apparatus described above, the cooling power of the cooling device is merely controlled to keep constant the amount of the light emitted from the solid-state light source. Therefore, measures to meet the demand for reduction in power consumption are insufficient.